1. Field of the Invention
The present invention relates to a pharmaceutical composition for the treatment of urinary incontinence comprising DL- or L-threo-3-(3,4-dihydroxyphenyl)serine or a pharmaceutically acceptable acid addition salt thereof as an active ingredient.
2. Statement of Related Art
In the U.S.A., urinary incontinence, dementia and osteoporosis have been considered especially serious diseases for the aged people, and therapeutics therefor have become a medical and social problem awaiting prompt solution. Likewise in Japan, attention has been similarly brought to new medical problems for the aged people. Therefore, therapeutics for the aged people is desired to maintain and improve the quality of life in old age. In particular, urinary incontinence is a typical disease that deteriorates the quality of life of the aged people. Not only for the patients but also for their family, urinary incontinence is a serious burden. However, the patients usually feel ashamed of consulting about the urinary incontinence. In addition, therapeutics for urinary incontinence has not been extensively developed, because it would not be a fatal disease. Accordingly, only a few medicines for the treatment of urinary incontinence have been clinically used. For example, an anti-cholinergic agent, an .alpha.-receptor stimulator, an antidepressant, an estrogen, an autonomic nerve function modulator and a minor tranquillizer have been clinically used hitherto.
However, the anti-cholinergic agents and Imipramine which have been conventionally used have side effects such as thirst, constipation and nasal obstruction, and hence, their applications often accompany undesirable difficulties. In particular, an excessive anti-cholinergic activity causes micturition disturbance that is considered undesirable to the treatment of urinary incontinence.
After all, the more effective a medicine is in a principal action, the more serious it generally shows side effects. These side effects in many cases cause discomfort with the patients and fail to improve their quality of life.
Since most outpatients who suffer from urinary incontinence can spend their every-day life not much different from healthy people, it has been highly desired to develop an effective medicine for the treatment of urinary incontinence without side effects.